//
//  ExpressibleAsNSDate.swift
//  HealthSoftware
//
//  2020, Apple Inc.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

import Foundation

public protocol ExpressibleAsNSDate {
	
	func asNSDate() throws -> Date
}

public enum DateExpressionError: Error {
	case unableToExpressAsDate(DateComponents)
	case unableToConstructFromDate(Date, DateComponents)
}

extension ExpressibleAsNSDate {
	
	public func compare(_ other: ExpressibleAsNSDate) throws -> ComparisonResult {
		let selfDate = try asNSDate()
		let otherDate = try other.asNSDate()
		return selfDate.compare(otherDate)
	}
}
